Sex cord stromal tumors of the ovary account for about 5% to 8% of all ovarian malignancies. This group of ovarian neoplasms is derived from the sex cords and the ovarian stroma or mesenchyme. The tumors usually are composed of various combinations of elements, including the “female” cells (granulosa and theca cells) and “male” cells (Sertoli and Leydig cells), as well as morphologically indifferent cells. A classification of this group of tumors is presented (

Table 118-12).